Amphibian propulsion mechanism



July z3; 1946. J. M. Hm 2,404,486

AMPHIBIAN PROPULSION MECHANISM Filed Jan. 8, 1942 Patented July 23, i946 umm 2,404,486 .y y PROPULSIONMECHANISM .lames Hait,l San Gabriel, Calif.,j assigrnorfto.V

Food Machinery Corporation,San Jose, Calif., a corporation of Delawareapplication JanuaryY s, 194,2,l serials@ .fir/6,0271A Asvcla'ims.V (01.115411)v This invention relates to amphibian tanks tof the endless track-laying type and has for its prin;y

cipal object the provision of an improved propulsion mechanism for use on such tanks totrans-` form the motive power into propulsive thrust vwhen thetank is floating in the water.A

'The manner of accomplishing" the foregoing object,- as wellas'further objects' and advantages, will be made-manifest infthe following description taken .in connection with" the accompanyingv of the latter being secured to each side of the hull I2. Trained about each set of these sprockets and wheels is a ilexible endless belt I4.

The belt I4 is provided with grcusers I5 which extend downwardly therefrom substantially at right angles from the plane of the belt. AThese grousers support the belt I 4 and the tank I I when the latter is traveling on land and are depended upon, when the tank is traveling through water, to engage the water and propel the tank.

In exhaustive'laboratory tests, I have found the grouser blades I5 to exhibit a high degree of efliciency. It is also to be noted that these grouser Whilevthese grousers I5 may be employed out anyintermediate grousers disposed therebe--` tween, it has` been-found`expedient lto place a half grouser 2| on the middleplate of each set 'j of three required for,v supporting afcomplete grouservIS. The relation ofthe gr`ousersfvl5l and half grousers 27| are clearlyfshown in'Fig. ,2.l2t' is to b noted that each grouser I5 hasa straight portiorr- 2511which4 is relatively long `and;disposed;

at a sharply acute anglerelative tov the,y direction of traveluof .theigrouserls on the belt-I4,v as indicated by arrows 26. :Towardfitsouter-,or,rear end each grouser I5 has/a curved portion52'I forming a reaction cup 28.

WhenV the tank II is oating in water,` and the belts I4 are driven in the direction indicated by Ythe arrows 26, the grousers I5 and half grousers blades are adapted to be mounted in a telescoped relation which gives adequate transverse support tothe belt I4 when the wheels I3 pass thereover.

The belt I4 is preferably reinforced by a series of metal clamps I6 which are imbedded in the rubber of the belt I4. The clamps I6 are clamped onto a series of endless cables I1 also imbedded in the rubber of the belt so as to prevent the Each grouser I5 preferably extends across three of the plates 20.

. ative to each other.

2l operate to propel the tank through the water in the direction of the arrow 30. This is accomplished by the straight portions 25 of the grousers causing a Vrapid flowing of water therebetween.

TheV straight blade portions' 25 offer relatively little resistance to this water movement. 'I'he masses of water thus set in motion however are caught within the cups 28 formed by the curved portions 21 of the grousers I5 and in the half grousers 2| to cause 'a reaction which throws this water downward and toward the rear. This sets up a relatively high resistance to travel of the belts I4 in the direction of the arrow 26. This naturally increases the thrust imparted to the hull I2 of the tank II in the direction of the arrow 30. v

In my experiments I have noticed that the grousers I5 have a marked superiority in per-l formance when placed at approximately 50 degrees with respect to the side of the tank II, over the performance that these blades .have when they are placed with the chord thereof' at right angles to the side of the tank.

Maximum eiiicency is attained with the grouser I5 when the substantially straight portion 25 is relatively long as shown in the drawing. This length would make this grouser impractical lor use on an amphibian were it not for the feature of dividing each grouser transversely into sections capable of articulation relto readily pass around the idle and driven sprockets (not shown) and the bogie wheels,

adapt itself to uneven terrain, and supply uni- This permits the grouser vcombination of: A 'Y mounting said belt on said amphibian for annular movement; and aseries of propulsion grous-v ers on Vsaidrbelt, each grouser being disposedY with thetip to tip chord thereof'at an acute,

angle with the direction of movement of said-j grousers on said belt, the mostiforwardly Vdis-V vposed portion of each grouser being relatively long and substantially straightv and disposedV at f a smaller angle with respect tox'said direction than said chord,rwhi1e the rearmost portion of said grouser is relatively sharply curved. toward f the direction of movementrof said grousers. Y

2. In an amphibian propulsion mechanism, the

combinationA of: van endless belt; means for mounting said? belt lonV said amphibian for annular movement; anda series of propulsion grousers on'sai'd belt, each grouser being' disposed With'the tiprt tip 'chord thereof at aniacute angle of" from about 40 to 60 degrees WithY thev direction of movement ofsaid' grousers on said belt, the most forwardly disposed portionr of each grouser being relatively longV and substan- Vtiallystraig'ht and disposed at a smaller'. angle with respect to said direction than said* chord, while the rearmost portion of said grouser is relativelysharply curved toward the'direction of e movement of said grousers. n v

3. 'In an amphibian mounting said belt on said amphibian for annular movement; and arseries of propulsion grousers on said belt, each grouser ybeing disposed With the tip to Vtip chord thereof at an acute angle ofapproximately 50 degrees With the di rection of movement of said' grosers on said belt, the most forwardly disposed 'portion Vof`Y yeach grouser being relatively long and substan-Y 4 l tially straight and disposed at a smaller angle f with respect -to ysaid direction Vthan said chord;

While theV rearmost portion of said grouser is relatively sharply curved toward the direction of rriovment'ofv said grousers. Y

V4. A combination as in claiml in' which a semi-grouser comprising a curved blade substantiallyv like the curved portion of the aforesaid grouser is disposed between adjacent pairs of the aforesaid grousers in positions correspending to the positions of the curved portions Aof VVthe aforesaid grousers, the space between straight portions of adjacent grousers being sub'- stantially unobstructed. Y 5. A combination as in claim lgin Whichfsaid grousers-are divided transversely of the.; direc-vr tion iniwhich they travel each grouserbeingdivided'into a plurality of sectionssaid sections being. adapted to'articulate one relative to'y theV other when said belt bendsv around aturning n axis.

JAMES M. HAIT.

propulsion mechanism, the combination of: anV Aendless belt; means for` 

